The performance of electric and electronic circuits can be adversely affected by unwanted disturbances due to electromagnetic conduction or electromagnetic radiation emitted from an external source. Such unwanted disturbances can interrupt, obstruct or otherwise degrade the effective performance of the electric and electronic circuits. Housing structures for shielding electric and electronic circuits from external electromagnetic interference (EMI) have been developed. EMI shielding is generally achieved by having the housing structures configured to limit the penetration of electromagnetic fields into the enclosed spaces within. The housing structures, fabricated using conductive materials are known as “Faraday cages,” which operate as barriers to block the electromagnetic fields. More particularly, and as is known in the art, a Faraday cage is an enclosure formed by a conducting material and can be used to block external electromagnetic interference. When the housing structures are subjected to external electromagnetic forces, electric currents are generated in the conductive housing structures, which electric currents, in turn, produce electromagnetic forces opposing and cancelling the external electromagnetic fields.
Likewise, lightning protection systems utilize conductive housings to provide a low-impedance path for lightning currents while reducing the heating effect of the currents flowing through the conductive housing structures. These reduced heating effects mitigate fire hazards due to lightning strikes.
Generally, conductive materials used for fabricating such EMI shielded housing structures and/or lightning protection applications include highly conductive metals such as copper and aluminum. These metals, however, are relatively heavy. Lighter materials such as composites or “composites,” even those made from conductive fibers such as carbon, are typically insulating and therefore have poor EMI shielding and lightning protection characteristics, due to the presence of the matrix material (e.g. resin). Such composites, although desirable for their given characteristics, are not suitable for applications which require good EMI shielding and/or lightning protection characteristics.
To improve the EMI shielding and the lightning protection characteristics of composites, metal fillers, metal coating, metal meshes, or other metal components have been incorporated in composites. However, such incorporation results in heavier and more complex composites. Alternative composites suitable for use in EMI shielding and/or lightning protection applications are desirable. The present invention satisfies this need and provides related advantages as well.